The tropical disturbance in the Caribbean is still expected to bring extra rain to the southeast U.S. from Louisiana to Florida, likely beginning by Saturday. Note that frequent afternoon/evening rain is already occurring in these areas due to a moist air mass that has persisted since last week. The disturbance will move northward into the Gulf of Mexico and generate more consistent heavy rainfall, potentially for several days, as it will be moving slowly.

The National Hurricane Center now gives a 60% chance of subtropical or tropical cyclone formation within the next 5 days. However, the potential for flooding due to heavy rains will occur even if the disturbance does not develop, so be prepared for excess rainfall into next week. Your local National Weather Service office will have more specific details for your local area as the event nears.

A strong upper trough reaching down into the Caribbean has spurred the development of a surface trough north of Honduras. Lots of wind shear and dry air are currently preventing development, but the disturbance will gradually track northward into the Gulf of Mexico by Thursday, and if it becomes vertically stacked beneath the upper trough, some subtropical or tropical development is possible. Models currently disagree on how far west or east the disturbance will track, with the GFS moving the system over the Florida Peninsula, and the ECMWF toward the central gulf coast. At this point, I would tend to lean toward the ECMWF track due to what appear to me to be convective feedback issues in the GFS. However, given the broad and disorganized nature of the system, there is a fair bit of uncertainty in its eventual track.

Regardless of the disturbance’s track, or even whether it develops, Florida will continue to receive periods of heavy rain throughout this week due to the tropical moisture flowing up the eastern side of the system, leading to potential flooding hazards. Considerable rain may fall along the central and eastern gulf coast states as well, especially late this week. The disturbance will move rather slowly on its way northward due to weak steering currents, leading to substantial accumulations. This rain is currently expected to be the primary impact from this system.

As of Monday evening, the NHC gives a 40% chance of subtropical or tropical cyclone formation during the next 5 days. Any development will be very gradual during the next 2-3 days while the system remains messy and sheared, and it is currently uncertain whether significant development will occur after midweek. Stay tuned to the National Hurricane Center and your local NWS office for the latest information.

An area of surface low pressure has developed in the eastern Gulf of Mexico, entangled with an upper-level low. The system remains broad and disorganized this Monday morning, with only scattered convection and multiple vorticity maxima at various vertical levels. As a broad upper low or trough remains over the Gulf of Mexico over the next few days, wind shear will be low enough to allow potential organization of this disturbance. Given weak steering currents, the system is expected to drift north or northwestward, eventually moving inland over the Florida panhandle in 2-3 days. This length of time could allow the low to acquire subtropical or tropical characteristics, and the National Hurricane Center currently gives a 40% chance of this occurring.

Regardless of how much this system develops, periods of heavy rain will continue in the Florida Peninsula, and will spread northward into the Florida panhandle and parts of Alabama, Georgia, and the Carolinas over the next few days.